Keytruda is a brand name for pembrolizumab, which is a monoclonal antibody used to treat various types of cancer. Like any medication, Keytruda may cause side effects. The severity of the side effects may vary from person to person, and some may experience no side effects at all.

According to the sources provided, the side effects of Keytruda can be reversible. The long-term effects of Keytruda have been studied, and some of the side effects can last for months or years, while others may resolve on their own. The long-term side effects of Keytruda may include fatigue, joint pain, skin rash, and changes in vision.

It is important to note that Keytruda can also cause severe side effects, such as pneumonitis, colitis, hepatitis, and endocrinopathies. These side effects may require treatment and can be life-threatening.

In summary, Keytruda may cause side effects, and the severity of these side effects may vary from person to person. Some of the side effects can be reversible, while others may require treatment and can be life-threatening. It is important to talk to your doctor about any concerns or questions you may have about Keytruda or its side effects.

Sources:
[1] https://www.drugpatentwatch.com/p/biologics/tradename/KEYTRUDA
[2] https://www.goodrx.com/pembrolizumab/long-term-effects-of-keytruda
[3] https://www.cancer.gov/news-events/cancer-currents-blog/2021/immune-checkpoint-inhibitors-melanoma-long-term-side-effects